Asurge of new housing can ease San Francisco's high prices and reshape a whole neighborhood. That's the upshot of a deal to build 1,700 units on the site of a former lock factory that should improve a long-neglected corner of the city.

The Schlage property near the city's southern border on Bayshore Boulevard was a sore point for years. Abandoned when the lock-making firm left the city in 1999, it defied a series of makeovers while the Visitacion Valley neighborhood wondered whether the broken windows and weed-choked acres would ever change.

After fresh bargaining that overcame daunting finances, the United Paragon development firm will build 1,679 rentals and condominiums with 15 percent at below-market rates. The rest of the units are planned to be within the financial reach of the city's middle-income residents, increasingly shut out of a skyrocketing housing market.

If San Francisco is serious about easing the housing crunch, it will need major steps like this one. The number of units in this plan equals the city's feeble yearly production only a few years ago. Mayor Ed Lee, who played a role in nursing the Schlage deal along, has a wish-list goal of 30,000 new homes or apartments by 2020.

The Schlage spot will be more than an apartment complex. It will include a modest supermarket, which the adjacent neighborhood has long wanted, along with a community center and parks. The location sits near to a Muni light-rail line, making a car-free trip to a downtown job easy.

It took over 20 years to get this far. A big-box hardware store stalled amid local protests. Next, a housing scheme to tap redevelopment money died after Gov. Jerry Brown did away with the financing concept. District Supervisor Malia Cohen worked with the builder and the mayor's office on the latest design, which should end this saga and produce housing at last.

When fully built over the next decade, the Bayshore site will host nearly 4,000 residents. It will should bring new life to a neglected area and help ease the city's critical housing needs.